Reducing salmonella risk in table egg production

Quick facts

Purchase chicks from hatcheries in the United States Sanitation Monitored program and pullets from sources with salmonella prevention and control programs.

Control rodents, insects and wild birds on your farm.

Clean, wash and disinfectant poultry houses between flocks.

Monitor bacteria on your farm through laboratory testing.

Attend to feed quality control and proper feed storage.

Properly wash and store eggs to prevent salmonella contamination.

Have a strong and strict biosecurity program for your farm.

Chick and pullet replacements

Chickens are very prone to salmonellosis at two ages.

1 to 14 days of age

When pullets move to laying houses

Optimal nutrition and care can help keep your birds healthy and reduce the risk of salmonella at these ages.

Purchase your chicks from hatcheries taking part in the United States Sanitation Monitored program. Get your pullets from sources with good salmonella prevention and control program.

Have a reputable hauler for your pullets. Make sure the pullets travel in clean coops and trucks. Undisinfected coops commonly carry salmonella.

Vaccines

Bacterin can stop vertical transmission of salmonella in turkeys. Salmonella vaccination research is underway at the Universities of Maine and Minnesota and other places. Early signs suggest that bacterins also reduces the spread of salmonella in chickens via feces and eggs.

Some companies produce bacterin for commercial use.

Controlling rodents, insects and wild birds

Vectors are organisms that can spread disease. Vector control throughout your flock’s life is key to reducing salmonella.

Work routinely with a licensed professional rodent and insect exterminator.

Be sure that personnel practice strict biosecurity steps for their clothing, equipment and vehicles.

Make sure service providers have a good vector control record with poultry operations.

Rodents

Rodent feces can contain infectious amounts of salmonella. Mouse feces, common in feed troughs, may amplify salmonella disease in poultry. Rodents also carry disease to near and distant houses and farms.

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Remove all cover for rodents inside and outside the poultry house. This may include:

Shrubs or tall grass

Garbage or construction debris

Broken equipment

Burrows under the foundation

Set up a rodent barrier around the outside of the poultry house.

Seal all entrance holes inside and outside the building.

Fix and close siding sheet seams.

Make sure doors and door frames fit tight.

Seal holes and cement cracks in manure pits.

Make sure rodents don’t reside in reused filler flats, which can move to and from farms during egg delivery.

Caution: All baits are harmful to rodents, chickens, animals and people.

Preparing to bait

Remove all feed from feeders right after house depopulation, so rodents promptly go to the bait.

Remove all other food sources such as spilled feed, broken eggs and dead birds.

Check the outside of buildings often for rodent holes.

Selecting bait

Warfarin, diphacinone and pival are rat poisons that work by thinning the blood. To be effective, rats must receive these poisons in multiple doses over several days. Thus, poison works best if you use it routinely, every two weeks.

Newer blood thinners contain brodifacoum and bromadiolone. These may cause death three to five days after a single feeding. You can use single-dose rat poison at any time, especially right after house depopulation.

Make sure to stock enough rat poison to meet the long-term need of the farm.

Placing bait

Place baits to avoid contaminating feed and eggs or coming in contact with poultry and humans.

Don’t place bait loosely on the ground in high-traffic areas. People may carry it on their shoes and contaminate sensitive areas.

Save bait by only baiting holes with rodent activity.

Fill all rodent holes with dirt or paper.

Check for open holes later.

Only bait the open holes.

Follow the manufacturer’s directions when placing the bait.

Control attic rodents by making a hatch for attic access and bait with a high-wax single-dose poison at least once yearly.

After controlling rodents, inspect and keep up permanent bait sites every two weeks. Record the location and numbers of trapped mice and maintain these records.

Insects

Using several practices to control insects reduces the chance of insects adapting to a single method.

For example

Keep manure well ventilated and dry.

Prevent water leaks and remove wet areas.

If possible, use biological control methods (fly parasites and predators).

Use different types of insecticides.

Applying insecticide

Clean and disinfect the poultry house floor.

Once the floor dries, apply an approved insecticide to the floor, support poles and walls.

Always follow the manufacturer’s safety precautions.

You can use synergized pyrethrins (pyrethrin plus piperonyl butoxide) in automatic spray systems inside poultry houses. These quickly knockdown flying insects, have short residual times and have low toxicity in mammals. Don’t apply these insecticides more than twice weekly, especially if you use a spray system.

Wild birds and pets

Avoid feed spills outside the buildings and clean up any spills right away.

Buildings should keep out wild birds and prevent them from sitting under eaves or on blinds.

Keep pets out of pullet and layer houses.

Cleaning facilities

Always clean pullet and layer houses between flocks to reduce possible buildup of disease agents, such as salmonella.

Clean facilities as soon as you remove the birds if any tested positive for salmonella. Cleaning will prevent replacements from contamination.

Good cleaning programs need to:

Be put in place across the entire farm

Have proper equipment

Have professional training

Cleaning conventional facilities presents a big challenge due to the following.

These problems decrease how effective cleaning plans are. In the past, many used formaldehyde to help disinfect porous surfaces. Although effective against salmonella, its use comes with human safety concerns, poor product availability and regulatory policies. Other options may help disinfect porous surfaces.

Other fumigants

Heat-enhanced disinfectants

High-pressure sprays or disinfectant foams

Sealants to reduce the rough surface of wood

Step-by-step cleaning

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Remove all dead and live birds from the building. This includes all escaped birds in the deep pit or outside. Start vector control procedures right away during bird removal.

Moving from top to bottom, clean up the dust inside the building. For example, remove dust from the ceiling, beams, walls, cages etc.

Promptly open feeder lines and remove all feed including feed inside troughs.

Open egg conveyance equipment at the front of the building and remove all dust and egg debris. Remove broken and soiled parts that you can’t clean.

Do your best to remove manure from dropping boards.

Remove all litter and manure from floor or cage houses, including augers and pit ends.

Be aware of National Institute for Occupational Safety and Health alerts on manure pit hazards.

If you can, fill trailers with manure inside the house and cover it before hauling to a disposal or composting site. Manure should not be spread near poultry facilities.

Remove egg belts and sweep away all debris above and below the belt.

Remove all debris and items not needed from the entire building.

Turn off power to electrical equipment prior to cleaning. Use compressed air or brushes to clean non-removable motors, switches, etc. Take extra care to keep sprays out of electric motors. Use duct tape to cover the motor slots before wet cleaning and disinfection. Remove the tape after wet cleaning and disinfecting.

Soaking and washing

Soften dirt in heavily soiled areas. Use a low-pressure (200 to 300 pounds per square inch) sprayer, which delivers 10 to 30 gallons per minute. Hot water and cleaners can help loosen debris and films that salmonella can grow in.

While washing, start at the back and work toward the front. Spray the ceiling first, then the walls and lastly the floor. Thoroughly clean everything.

Use sprayer attachments and nozzles that allow you to wash hard-to-reach places.

In the past, producers used formaldehyde (formalin) to disinfectant for salmonella. Producers also used formaldehyde fumigation (gas) as a final crack- and pore-cleaning step if relative humidity was at least 70 percent and temperatures were at least 70 F.

Preparations for restarting

Repair and adjust your egg handling and conveyance system from hen to cooler.

Remove old water filters. Clean and disinfect casing and install new filters.

Restock restrooms and portable toilets with soap and paper towels.

Make sure that all electrical equipment work properly.

Clean all equipment used for washing and disinfecting the facility and store them in a clean, secure space.

Monitoring bacteria

You must monitor bacteria through laboratory testing to complete your quality control program. Monitoring helps keep track of how well you’re reducing risk. Lawyers suggest that knowledge of a problem is better than none.

Collecting samples

Sampling often requires on-the-spot judgements. How you collect samples is more important than how many you collect. Poor sampling or laboratory methods can result in a false negative reading. Choose a laboratory that follows good salmonella culture methods.

Monitoring plans and schedules

State laws, regulations and policies differ on the privacy of voluntary monitoring to help gain research, disease and in-house quality control data. Positive results during any bacteria monitoring times (see table 1) may present complex fiscal, legal and ethical issues. The same may be true for if you don’t monitor. Work with professionals (legal, underwriter and veterinary) to develop monitoring programs and choose from the following examples for pullet and layer flocks.

Gather eggs frequently

Properly wash eggs

In-line washing systems

Wash the eggs and cool to 45 F or less. Use only potable water with a maximum iron content of 2 parts per million and a minimum wash water temperature of 90 F.

Nest run systems

Cool the eggs right away to 60 F until you wash them. This will avoid cracks during washing. If the egg and wash water temperatures differ by 50 F or more, you may need to pre-warm the eggs before washing. Make sure the wash and rinse solutions are 10 to 15 F warmer than the eggs.

Use sanitizers following the manufacturer's recommendations.

After washing, cool the eggs to 45 F or less if sweating can be controlled.

Provide good storage and transport temperatures

Eggs should remain at 45 F during storage and transport.

Control inventory

Rotate the product at all levels of distribution, warehousing, sale and home or institutional use. This inventory control decreases the likelihood of salmonella growth in the product.

Have proper food labels

State on egg carton labels that eggs are a perishable (will spoil) food and require the same care, including cooking, as other animal source foods. More informed consumers benefits both producers and their customers. Store eggs in their original carton in the main section of the refrigerator and not in the door shelf, where it can reach 60 F.

Don’t reuse fiber flats and egg cartons. Reusing these can save you money but they can lead to disease spread. Plastic flats are more ideal for reuse, but you must wash and disinfect them after each use.

Salmonella can contaminate both the egg shell surface and the inside of the egg. Salmonella contaminates the inside of an egg either before the egg fully forms or by entering the shell.

Proper egg washing and sanitizing can rid egg shell surfaces of salmonella but not salmonella inside the egg. Cool temperatures play a key role in preventing further salmonella growth inside eggs.

Egg white contains products that help kill or stop the growth of bacteria. These natural products become less effective as the egg whites age. Cool temperatures help slow egg white aging and thus, help it control bacterial growth.

Cold temperatures alone can also prevent or reduce the growth of salmonella organisms. Research shows that Salmonella enteritidis put into eggs, didn’t grow at 40 F, but did grow at 50 F. Thus, by reducing egg temperature to 45 F or lower, you can reduce the risk of salmonella growth.

Feed and water

Many salmonella types have been found in feed and feed ingredients. You must prevent salmonella contamination after manufacturing. Take care in selecting feed suppliers and in shipping and storing feed.

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Obtain feed from mills that follow the guidelines:

Recommended Salmonella Control for Processors of Livestock and Poultry Feeds, published in September, 1988 by the American Feed Industry Association, 1501 Wilson Blvd., Suite 1100, Arlington, VA 22209.

Competitive exclusion (CE) refers to the natural gut bacteria that protect the bird from pathogens. You can buy and feed CE to your flocks.

Prompt post-hatch founding of CE gut bacteria, with a clean environment, may help reduce the risks of salmonella growth in the gut of normally prone, young fowl. CE cultures seem to help speed the growth of a possible protective gut bacteria. Probiotics aren’t quite the same as CE cultures.

Biosecurity

Biosecurity practices that prevent most diseases are equally good within a salmonella risk reduction program. Salmonella infects flocks when a virus or disease agent weakens your flock’s natural defense. Thus every step in biosecurity is an investment in flock survival.

People can also aid in spreading salmonella to chickens and eggs. Thus, all farm workers must have good hygiene. Provide clean, working toilets with hand washing and drying facilities to serve all employees.

Provide training materials such as videos or pamphlets to employees at all levels. Review such materials regularly and add practices as you see fit for your farm.

Biosecurity checklists

Checklists for flock caretakers and farm managers

Flock caretakers

You can post this list in all poultry houses. Consider printing large, clear posters.